Canola is an edible oil that
is extracted from two oilseeds crucifers, Brassica rapa (= campestris) L. and B.
napus L. Using conventional plant breeding techniques, selections that were low in
seed glucosinolates and euric acid were developed in Canada, and referred to a double-low
rapeseed or canola. Canola can be produced either as spring or fall planted crop,
depending on location.

In the North Central Region,
it is a spring planted crop in North Dakota, South Dakota, and Minnesota. The crop is
usually planted in late April or early May and harvested in August and September. Canola
is usually produced in rotation with small grains. Tillage is conventional with
sweep-tillage and seeded with an air-drill or press drill. It is seeded at a rate of 5 - 8
lbs in 6 - 8 inch row spacing.

In the Pacific Northwest, it
can be either a spring or fall planted crop in Washington, Oregon, Idaho, and Montana. A
fall planted crop is usually seeded in September and harvested in July. A spring planted
crop is usually seeded in April or May and harvested in August. Canola is grown in
rotation with winter or spring wheat, barley, peas, or lentils. Tillage is usually
conventional with sweep tillage and seeded with either with an air-drill or press drill.
It is seeded at a rate of 5 - 8 lbs in 6 - 10 inch row spacing.

In the Southeast, canola is
grown in Georgia, South Carolina, Alabama and northern Florida. The crop is planted in
October and harvested in May. Canola usually is double cropped following corn, peanuts,
cotton, or tobacco with summer crops planted after canola being soybean, cotton, or grain
sorghum. Tillage usually is conventional with chisel plowing and/or disc harrowing.
Typically 5-6 lbs per acre of seed are planted in 7 to 10 inch rows using a grain drill.
All canola grown in the Southeast is genetically engineered to produce lauric acid as part
of the oil in the seed. (Canola oil normally does not produced lauric acid). Oil extracted
meal typically is used a livestock and poultry feed.

Northern Plains: North
Dakota, Minnesota, Montana, South Dakota
1996 Acreage: ND 230,000 (53 % of national acreage), MN 69,000 (16%), MT 50,000 (12%), SD
7,000 (2%). Total acreage was 356,000 with 83% of the national acreage. The yields range
is 1,200 to 1,700 lbs per acre or 37 - 53 bushels per acre.

Pacific Northwest: Idaho,
Washington, Oregon
1996 Acreage: ID 25,000 (6% of national acreage), WA 20,000 (5%), OR 12,000 (3%). Total
acreage was 57,000 with 13% of the national acreage.

Southeast: Georgia,
Alabama, Florida, South Carolina
1996 Acreage: GA 8,500 (2% of national acreage), AL 3,000 (0.6% of national acreage), FL
200 (0.04% of national acreage) SC 350 (0.05% of national acreage). Total acreage was
11,700 with 2.7% of the national acreage. The yield can be up to 2400 lbs/acre with an
average of 25 bu/acre.

The total production acreage
for 1997 in the US was 730,000 acres, a 42% increase in production over 1996. Production
costs vary within the US, but in North Dakota direct production costs are estimated at
$60.42 per acre with indirect costs estimated at $55.11 (Swenson and Aakre, Crop Budget
Series 1998). The return to management and labor is estimated at $32.07. In the southeast,
variable and fixed costs for canola production average $133.00 and $46.00, respectively,
for a total cost of about $179.00 per acre (Hudson & Woodruff 1995). The average net
return for canola was about $21.00 per acre ($8.00/bu and average 25 bu/acre). In the
Northwest, direct production costs for spring canola are estimated at $147.58 per acre
with indirect costs estimated at $81.15. Net returns above direct operating costs are
estimated at $8.42 per acre, and returns to risk and management at -$72.73.

Northern Plains

Flea beetle(Phyllotreta
crucifera) is an early season pest of canola, especially during hot and dry weather.
Adult beetles overwinter in shelterbelts, fly into the emerging canola crop, and feed on
cotyledons. The crop becomes tolerant to injury after the appearance of true leaves.
Beetles mate, lay eggs and die. The larvae feed on canola roots. The new generation of
adults emerges in summer. The beetles feed on remaining green foliage and pods, but the
injury is usually negligible. In late summer, they move to the shelterbelts to
overwinter.
The management options for flea beetles are early planting, insecticides applied at
planting, and foliar application of insecticides. Lack of moisture may limit uptake of the
soil-incorporated insecticide into the plants, which may cause insecticide failures.
Insecticides currently available are carbofuran (Furadan CR-10, temporary tolerance
expires in the fall of 1997) and Imidacloprid (Gaucho). Gaucho is applied as a seed
treatment at 10 oz per 100 lbs of seed and carbofuran is applied as a corn cob grit
granular at 0.25 lb AI per acre. Based on a survey of producers in the Northern Plains,
about 60 - 70% of the acreage is treated with either carbofuran or imidacloprid.

Bertha armyworm (Mamestra
configurata) is a mid- to late season pest of canola. It overwinters as pupae, the
adults emerge, and lay eggs in the late spring. The larvae feed on foliage. While the
larvae are small and the crop has abundant foliage, the damage is low. During the ripening
stage startng in late July, mature larvae feed on pods and cause significant damage. For
monitoring of adult flight, pheromone traps are available. Management decisions are based
on counts of larvae. As a cultural control, early swathing may be an option in infested
fields. The recommended threshold for insecticide applications is 18 - 22 larvae per
square yard. North Dakota has had section 18 labels for bifenthrin (Capture) and lambda
cyhalothrin (Warrior) in 1995 and 1996, respectively.

Diamondback moth (Plutella
xylostella) is a late season pest of canola. Areas in the North Central region are
infested every spring with adult moths migrating from the south part of the region. Once
established, a new generation occurs approximately every three weeks. The generations
overlap and any of the life stages can be found in the field. Young larvae feed in mines
in leaf mesophyll whereas older larvae feed on leaf surface. Damage may occur during
flowering and ripening when larvae feed on buds, flowers, and especially on the surface of
ripening pods. The recommended threshold is 25 - 30 larvae per square foot. Methyl
parathion and endosulfan are the only registered products for this pest.

Southeast

Aphids (Complex consisting of
turnip aphid, Lipaphis erysimi, green peach aphid, Myzus persicae, and
cabbage aphid, Brevicoryne brassicae). Turnip and green peach aphids migrate into
fields in the fall and feed through flowering in the spring. Cabbage aphid mostly occurs
during flowering in the spring. Aphids disperse after flowering. Feeding injury mostly by
the turnip aphid during seedling and rosette stages retards plant growth and makes plant
more susceptible to cold temperature injury. Feeding injury during flowering reduces stem
growth, causes flower abortion and inhibits pod and seed formation. Aphid resistant
varieties are not available. Aphids caused about a 10 to 30% loss in canola yield if not
controlled with an insecticide. Aphids populations can be naturally controlled by the
weather and by natural enemies including a parasitic wasp and ladybird beetle larvae and
adults. Fields are scouted for aphids. When populations exceed a threshold of 1-2 aphids
per leaf, infestations are controlled using a foliar application of methyl parathion 4EC
at the rate of 0.5 lb ai per acre. Gaucho seed treatment at the same rate recommended for
flea beetle control also provides good control of aphid populations for 4 to 8 weeks after
planting. A 12 month planting restriction currently prevents crops from being planted
after canola unless Gaucho is registered for use on that crop which in the Southeast these
crops are limited to cotton and grain sorghum. Soybeans can not be growth within 12 months
after canola treated with imadcloprid. Endosulfan also is registered for aphid control but
is not used because it is less effective especially against green peach aphid and is much
more expensive than methyl parathion.

Cabbage seedpod weevil (Ceutorhynchus
assimilis) does not occur in the coastal plain region of the southeastern U.S., where
all commercial production currently is grown. The insect does occur in northern Georgia,
Alabama, and South Carolina and would require preventive control if canola were ever grown
in these areas of the Southeast.

Canola also harbors populations of
thrips, (Frankliniella
spp.), tarnished plant bug, (Lygus lineolaris), stink bugs, and false chinch
bugs, (Nysius raphanus), during the spring. These insects typically do not damage
the canola but build up on the canola and move the summer crops especially cotton in the
same or adjacent field where they may cause significant damage.

Pacific Northwest

Cabbage Seed Pod Weevil, (Ceutorhynchus
assimilis) Cabbage seedpod weevils overwinter as adults near canola fields in
protected area such as under bark of trees, sheds, wood piles, and litter. Adults start
flying in the spring when the temperature reaches 60 degrees F, the time when wild
mustard, winter rapeseed, and canola plants start to bud. Adults feed on the flowers,
buds, stem, and pod of the canola. When they fly into the canola field they have mated and
are ready to lay eggs. The first eggs are laid when the pods are about 1-1/8 inches long.
Eggs are laid within the pod, larvae feed on seeds within the pod, consuming 4 to 6 pods
each. More than one larva can occur in a pod. Yield reductions to 30 percent are possible
from larval feeding. Larvae eventually exit the pod, drop to the soil to pupate, and
emerge as new adults. The newly emerged adults feed on canola and brassica weeds and move
to overwintering sites. There is one generation per year. Late spring plantings may escape
weevil attack, but are then more subject to flea beetle, aphid, and diamondback moth
attack, and hotter weather. Control is limited to methyl parathion and
endosulfan.

Aphids The same three species as
in the southeast region attack spring-planted canola in the northwest. Late plantings are
severely affected by aphid feeding, which can stop terminal growth leading to a reduction
in plant size and seed yield. Control has been limited to methyl parathion and a Section
18 label for bifenthrin.

Flea beetle (Phyllotreta
cruciferae) attacks fall-planted seedlings, late spring-planted seedlings, and
sometimes pods and leaves of spring-planted canola. See northern plains section for
biology. Furadan CR-10 was registered in Washington and Idaho in 1997. Foliar treatments
has been limited to methyl parathion, but it is not as effective as imidacloprid or
carbofuran.

Diamondback moth (Plutella
xylostella) damage occurs leaves, buds, flowers, and pods of plants. Damage may be
more severe on later plantings. Damage (numbers of insects) is more variable from year to
year then the other canola pests in the region. Migration of the moth may be from local
populations or populations that have developed in more southern latitudes. See northern
plains section for biology. Control has been limited to methyl parathion and Bacillus
thuringiensis (BT) products.

Wild oats (Avena fatua) is an annual grass and is primarily a weed in spring-seeded small grains. Wild oats flowers and
produces seed from June to August. Seeds can be dormant at least 10 years. Dormancy is induced by burying the seed after
deep tillage. Wild oats has become a major weed in the canola cropping system, because spring-seeded grains is predominant
in the crop rotation and the long seed dormancy. Current control methods are chemical.
Labeled compounds include trifluralin, sethoxydim, and quizalofop. Pre-plant incorporated trifluralin gives fair to good control and post-emergence treatment with
sethoxydim and quizalofop-P-ethyl gives good to excellent control. In Montana and North Dakota experiments, pre-plant
incorporated trifluralin gave excellent control of wild oats. Poast (sethoxydim) applied at third leaf stage of grasses provided
excellent control of wild oats. However, the majority of studies have indicated that trifluralin give poor to fair control of wild
oats.

Wild buckwheat (Polygonum convolvulus) is an annual plant in the Polygonium family. Wild buckwheat becomes more
prevalent when dicotyledons are introduced into the crop rotation; for example wheat - canola, or wheat - lentil, or wheat -
flax. Buckwheat in canola can be considered far less competitive than wild oats. Trifluralin, although
labeled for control of some small-seeded broadleaf weeds, gives poor control of wild buckwheat. Pre-plant incorporated trifluralin provided fair to good
control of wild buckwheat in Montana; however, this is the exception rather then the rule. With the exception of section 18
labels of clopyralid on canola, no registered herbicide controls wild buckwheat. Clopyralid gives fair to excellent control of wild
buckwheat.

Canada thistle (Cirsium arvense) is a perennial weed in the Composite family. Plants are dioecious and the male and female
flowers are on separate plants. Flowering occurs in July and August. Plants grow in patches and shoots emerge from deep and
extensive horizontal roots. Cutting roots through sporadic tillage without additional chemical control measures increases patch
and establishment and size. Canada thistle is a strong competitor, approximately 3 - 4 times more aggressive than wild oats.
The herbicides currently labelled in canola do not control Canada thistle. The best control option may be treatment in the fall
with glyphosate or clopryalid plus 2-4 D, prior to the season when canola is grown.

Green foxtail (Setaria faberii) is an annual grass. Flowering and seed production occurring in July to September. Data on
competitive ability of green foxtail with canola is limited. However, once suppressed early in the season, green foxtail may not
compete well with canola due to its smaller size. Currently labelled herbicides give excellent control of green foxtail.

Wild mustard (Brassica kaber) is an annual or winter annual plant of the Mustard family and is closely related to canola. Wild
mustard spreads with seed, and can be a contaminant in canola seed. Wild mustard seed can remain dormant in the soil for
many years. No chemical is available for control.

Quackgrass (Agropyron repens) is a perennial grass reproducing by seeds or by rhizomes. Broken or cut rhizomes remain
viable, therefore mechanical control is difficult. Quackgrass is about as competitive as wild oats. The labelled compounds,
quizalofop gives excellent control, sethoxydim gives fair control of quackgrass, whereas trifluralin gives poor control.

Redroot pigweed (Amaranthus retroflexus) is an annual plant from the Amaranthaceae. It reproduces with seed and seeds
can germinates any time when moisture is available . No-till systems may favor redroot pigweed occurrence in canola. Fair to
good control of redroot pigweed can be achieved with trifluralin. Excellent control may occur with pre-plant incorporated
trifluralin.

Russian thistle (Salsola kali) is an annual weed from the Goosefoot family. It reproduces with seed that germinates rapidly,
even after small precipitation. Russian thistle is a problem especially in dryer areas and in no-till systems. Trifluralin gives fair to
excellent control.

Pacific Northwest

In addition to weeds mentioned above, in the PNW the following weeds have been identifed as problem weeds,

Common Lambsquarter (Chenopodium album) is an annual weed from the Goosefoot family (Chenopodiaceae). Can be
controlled effectively with trifluralin. If not controlled, canola seed yield can be reduced depending on weed density. This weed
also can hamper harvest of canola.

Catchweed bedstraw (Galium aparine) is an annual or winter annual weed fromthe Madder family (Rubiaceae). Cannot be
controlled with existing registered herbicides. Seeds of catchweed bedstraw are about the same size as canola seed and are
difficult to separate. Canola seed quality can be reduced greatly if it is contaminated with catchweed bedstraw.

Southeast

Wild Radish (Raphanus raphanistrum) is the most important weed of canola in the Southeast. Wild radish is cruciferous
plant and a close relative of canola. As such, wild radish can not be selectively controlled in canola using herbicides. Radish
seed germinate throughout the fall the winter months, however canola can more effectively compete with radish germinating
later than 6-8 weeks after planting. Otherwise, radish can be very competitive with canola and can cause 20 to 40% yield loss
and well as contaminate seed with radish seed. Infestations are minimized by selecting fields with low levels of wild radish
infestations. The weed is controlled in a given field with herbicides in years when canola is not grown. Herbicide resistance
technology may have use in controlling weeds in canola in the future.

Italian or annual ryegrass (Lolium sp.) is a winter annual grass weed. Annual ryegrass is a common weed of all winter crops
in the Southeast. Trifluralin applied at planting will provide some control of ryegrass. A postemergence application of
sethoxydim (Poast) plus crop oil concentrate or quizalofop-P-ethyl provides excellent control of annual ryegrass when applied
as a foliar spray. Typically only a portion of fields are infested and require treatment.

Henbit (Lamium amplexicaule) and common chickweed (Stellaria media) are low growing, winter annual weeds. Both
weeds germinate in the fall, and infestations can compete with seedling and rosette stage canola. Severe infestations will retard
growth of canola seedlings. Trifluralin applied at planting provides good to excellent control of both weeds. Typically, henbit
and chickweed only occur in fields that are not treated at planting with
trifluralin.

Potential injury from herbicide carryover from summer crops is an important consideration in Southeast where canola is
grown in a doublecrop system. Sixteen herbicides used on cotton, peanuts, corn or soybeans have canola rotational restrictions
of 12 to 26 months. These herbicides are nicosulfuron, atrazine, primisulfuron-methyl, cyanazine, flumetsulam, metribuzin +
chlorimuron ethyl, chlorimuron ethyl, clomazone, Diuron, fluometuron, metribuzin,
linuron, imazethapyr, imazaquin, and norflurazon. Canola is extremely sensitive to herbicides such as chlorimuron ethyl and metribuzin + chlorimuron ethyl. Canola
also is sensitive to a number of broadleaf herbicides and can be injured by drift of herbicides applied to other fields (Hudson
and Woodruff 1995).

All Regions

Sclerotinia stem rot is most
severe in wetter areas and years. It is caused by fungus Sclerotinia sclerotiorum
which has a wide host range. The source of fungus is sclerotia in soil where they can
remain dormant for five years or more. During prolonged moist conditions and moderate
temperatures (at least for ten days), sclerotia produce apothecia that are the primary
source of spores. Spores are carried by air and land on flower petals which eventually
fall onto leaves and the growing mycelium invades the plant tissue. Contact moisture is
required for successfull infection. In the southeast, infection also can occur during the
rosette stage where mycelium grow on dead leaves still attached to the plant crown during
wet conditions in the winter. The recommended management strategy is crop rotation with at
least a four-year break between suceptible crops (beans, sunflowers, peas, lentils,
alfalfa, clover, carrot, and potato). However, crop rotation can reduce risk only within a
particular field and does not protect against air-borne inoculum from nearby fields. No
resistant varieties are available. No fungicides are labelled for use.

Blackleg is a disease also
favoured by moist conditions. The disease is caused by fungus Leptospheria maculans.
The source of inoculum could be infected seed or crop residue in the field. In areas not
infected previously with blackleg, seed is the source of infection; whereas in areas with
known incidence of the disease, infected crop residue is the main source of the disease.
Long-range infection of up to several miles is due to ascospores produced from the last
year's crop residue. Infected plants produce pycnidia spores that cause secondary or
short-range infection. The disease spreads over the plant and could infect the pods and
seeds. The recommended management strategy for preventing seed-borne infection is to use
healthy seed or treat seed with a systemic fungicide. Other practices are crop rotation
with an at least three-year break before planting canola and an isolation distance of at
least five miles from previous year's infected field. Cultural control also includes crop
residue sanitation and control of weedy and volunteer hosts. Some cultivars exhibit some
degree of resistance, especially Argentine types. No fungicides are labelled for foliar
application. Fungicide seed treatments of benomyl suppress seed transmission of blackleg.

Alternaria black spot is caused
by fungi Alternaria brassicae and Alternaria raphani. The disease is
favoured by warm humid conditions. The source of inoculating spores is infected crop
residue, infected seed, or cruciferous weeds. The spores germinate, penetrate the plant
tissue, and cause lesions that produce more spores. Management includes crop rotation with
at least three years without a host plant, control of cruciferous hosts of the disease,
sanitation, and using healthy seed. Seed treatment only suppress infection. Early swathing
may reduce shattering. Captan suppressess seed transmission of alternaria.

The US Canola Association is the key contact for pesticide issues for canola in the US.
This umbrella organization is the focal point for all state commodity groups. It has a
pesticide working group committee that solicts input from all state groups on key
pesticide issues. US Canola Association, Suite 1106, 1000 Connnecticut Ave., NW,
Washington, D.C. 20036 202/331-8113.